OrganisationDeep Dive
Blood Vessels: Structure and Function
Part of Blood Components and Vessels — GCSE Biology
This deep dive covers Blood Vessels: Structure and Function within Blood Components and Vessels for GCSE Biology. Blood composition, red and white blood cells, platelets, plasma, blood vessel structure and function, adaptations for transport It is section 5 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 16
Practice
18 questions
Recall
24 flashcards
Blood Vessels: Structure and Function
Arteries: High-Pressure Transport
Arteries carry blood away from the heart under high pressure:
- Thick muscular walls: Withstand pressure from heart contractions (120 mmHg systolic)
- Elastic fibers: Stretch during systole, recoil during diastole to maintain flow
- Small lumen: Maintains pressure for efficient transport
- No valves needed: Pressure gradient maintains unidirectional flow
- Smooth muscle: Can vasoconstrict or vasodilate to regulate flow
Veins: Low-Pressure Return
Veins return blood to the heart under low pressure:
- Thin walls: Lower pressure (5-10 mmHg) requires less structural support
- Large lumen: Reduces resistance to blood flow
- Valves present: Prevent backflow against gravity, especially in legs
- Less elastic tissue: Don't need to stretch like arteries
- Skeletal muscle pump: Muscle contractions help squeeze blood upward
Capillaries: Exchange Vessels
Capillaries are specialized for material exchange:
- One cell thick: Minimizes diffusion distance for gases and nutrients
- Tiny diameter (5-10 μm): Red blood cells pass in single file
- Extensive branching: Huge surface area for exchange (600 m²)
- Permeable walls: Allow water, nutrients, and waste to pass through
- Slow blood flow: Allows time for diffusion to occur
